AU2018352907B2

AU2018352907B2 - Rotating shaft of rotary compressor and rotary compressor

Info

Publication number: AU2018352907B2
Application number: AU2018352907A
Authority: AU
Inventors: Makoto Ogawa; Hajime Sato; Takashi Watanabe
Original assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2017-10-18
Filing date: 2018-10-18
Publication date: 2021-06-10
Anticipated expiration: 2038-10-18
Also published as: EP3677784A1; WO2019078293A1; JP6350843B1; CN111226039A; AU2018352907A1; EP3677784A4; JP2019074047A; CN111226039B

Abstract

This rotating shaft comprises a central shaft portion (17) which, when viewed in a cross section perpendicular to an axis line (O), protrudes in a direction intersecting an eccentric direction of a main-shaft piston rotor (14A) and a sub-shaft piston rotor (14B), and has an apex portion (17a) on an outer peripheral surface of the central shaft portion (17), at which apex portion (17a) the distance between the outer peripheral surface and the axis line (O) is maximized. The apex portion (17a) is disposed, with respect to a virtual line (Y) perpendicular to the eccentric direction and passing the axis line (O), at a position displaced by an angle (α) greater than zero degree and less than 45 degrees on the backward side in a rotational direction (R).

Description

DESCRIPTION

Title of Invention

ROTATING SHAFT OF ROTARY COMPRESSOR AND ROTARY COMPRESSOR

[0001]

Priority is claimed on Japanese Patent Application No. 2017-201554, filed

October 18, 2017, the content of which is incorporated herein by reference.

TECHNICAL FIELD

[0002]

The present invention relates to a rotating shaft of a rotary compressor that

compresses a fluid and a rotary compressor including the same.

BACKGROUND ART

[0003]

A reference herein to a patent document or any other matter identified as prior art,

is not to be taken as an admission that the document or other matter was known or that the

information it contains was part of the common general knowledge as at the priority date

of any of the claims.

[0004]

A rotary compressor applied to a refrigeration cycle such as an air conditioner

previously has been known. In such a rotary compressor, a rotating shaft, a bearing for

supporting the rotating shaft, a piston rotor eccentrically mounted on the rotating shaft, and a cylinder in which a piston rotor is disposed are mainly provided in a casing. In the rotary compressors, a fluid (refrigerant), which has flowed into the cylinder, is compressed by the rotation of the piston rotor.

[0005]

In recent years, the demand for high efficiency has increased in the rotary

compressor. For this reason, attempts have been made to reduce the size of a piston in

order to increase the displacement of the piston. However, in this case, there is a

problem in that a load acting on the piston increases and deflection easily occurs in the

rotating shaft.

Citation List

Patent Literature

[0006]

[Patent Document 1] Japanese Unexamined Patent Application, First

Publication No. 2013-181420

DISCLOSURE OF INVENTION

[0007]

For example, in Patent Document 1 the deflection of a rotating shaft is

suppressed using a technique, such as making the span between a main shaft part and a

sub-shaft part of the rotating shaft. However, the technique of suppressing the

deflection of a rotating shaft by optimizing the sectional shape of the rotating shaft is also

considered.

[0008]

The invention provides a rotating shaft of a rotary compressor and a rotary compressor capable of suppressing deflection of the rotating shaft to increase efficiency.

[0009]

According to one form of the invention there is provided a rotating shaft of a

rotary compressor that is rotatably supported with respect to a casing having a

compression chamber therein and is rotationally driven around an axis to allow a fluid to

be compressed with lubricating oil, the rotating shaft comprising: a shaft main body that

extends in a rod shape around the axis; a main shaft piston rotor that is eccentrically

provided at the shaft main body and is accommodated in a first compression chamber in

the compression chamber; a sub-shaft piston rotor that is disposed apart in a direction of

the axis from the main shaft piston rotor, is provided eccentrically with respect to the

shaft main body in a direction different in phase by 180 degrees from the main shaft

piston rotor, and is accommodated in a second compression chamber in the compression

chamber; and an intermediate shaft part around which the lubricating oil is present and

which is provided at a position sandwiched between the main shaft piston rotor and the

sub-shaft piston rotor in the shaft main body, wherein the intermediate shaft part

protrudes in a direction intersecting an eccentric direction of the main shaft piston rotor

and the sub-shaft piston rotor as viewed in a cross section orthogonal to the axis, and has

at least one apex where a distance between the outer peripheral surface and the axis is

maximized on an outer peripheral surface of the intermediate shaft part, wherein a pair of

the apexes is provided at positions symmetrical to each other with respect to the axis, and

wherein the intermediate shaft part has a shape in which only a portion of the apex on a

forward side of the rotational direction is partially cut off radially inward from one region

where an outer peripheral edge of the main shaft piston rotor and an outer peripheral edge

of the sub-shaft piston rotor overlap each other, when the intermediate shaft part is

viewed in a cross section orthogonal to the axis such that the apex is disposed at a

position shifted at an angle larger than 0 degrees and smaller than 45 degrees toward a backward side in a rotational direction with respect to an imaginary line passing through the axis orthogonally to the eccentric direction.

[0010]

According to such the rotating shaft of a rotary compressor, the apex of the

intermediate shaft part is disposed at a position shifted at an angle larger than 0 degrees

and smaller than 45 degrees toward a backward side in a rotational direction with respect

to an imaginary line passing through the axis orthogonally to the eccentric direction.

That is, the apex is not disposed on the imaginary line passing through the axis

orthogonally to the eccentric direction, and the diameter of the intermediate shaft part is

maximized at the position shifted toward the backward side in the rotational direction

with respect to the imaginary line. Therefore, the second moment of area of the

intermediate shaft part can be increased at this position where the apex is provided, and

the rigidity of the intermediate shaft part can be improved.

Here, the knowledge that the maximum load during compression acts in a range

larger than 5 degrees and smaller than 41 degrees on the backward side in the rotational

direction from the imaginary line with respect to the intermediate shaft part was obtained.

In the present aspect, the apex is disposed at the position shifted at an angle larger than 0

degrees and smaller than 45 degrees toward the backward side in the rotational direction

with respect to the imaginary line, and the rigidity is high at this position. Thus, even if

the thickness of the intermediate shaft part on the forward side in the rotational direction

from the apex is smaller than that of a columnar shape, the strength can be sufficiently

secured. Therefore, it is possible to secure the strength while reducing the weight of the

intermediate shaft part. Therefore, even when the load during compression from each

piston rotor acts on the rotating shaft, it is possible to suppress deflection deformation of the rotating shaft.

[0011]

Additionally, in the rotating shaft of the rotary compressor, the outer peripheral

surface of the intermediate shaft part may be disposed within one region where an outer

peripheral edge of the main shaft piston rotor and an outer peripheral edge of the sub

shaft piston rotor overlap each other as viewed in the cross section orthogonal to the axis.

[0012]

According to such a configuration, the apex is formed such that the outer

peripheral surface of the intermediate shaft part is cut off on the forward side in the

rotational direction of the apex. Hence, when the rotating shaft rotates, the lubricating

oil around the intermediate shaft part is smoothly guided toward the apex of the

intermediate shaft part, and smoothly flows along the outer peripheral surface of the

intermediate shaft part toward the backward side in the rotational direction. Therefore,

the stirring loss of the lubricating oil can be reduced.

[0013]

Additionally, in the rotating shaft of the rotary compressor, the apex may be

disposed at a position shifted at an angle larger than 0 degrees and smaller than 5 degrees

toward the backward side in the rotational direction with respect to the imaginary line.

[0014]

According to such a configuration, the apex is formed such that the outer

rotational direction of the apex. However, even in this case, the diameter of the

intermediate shaft part does not extremely decrease on the forward side in the rotational

direction of the apex, and the strength of the intermediate shaft part can be sufficiently

secured.

[0015]

surface of the intermediate shaft part may have an apex-side curved surface that is

disposed inside an outer edge of the one region and extends to be curved in a convex

shape in a direction away from the axis from the apex toward a forward side in the

rotational direction, and an eccentric-side curved surface that is smoothly continuous

with the apex-side curved surface and is provided at a position including an intersection

point between the imaginary line extending in the eccentric direction and the outer edge

of the one region to extend along the outer edge of the one region.

[0016]

By providing the apex-side curved surface and the eccentric-side curved surface

as the outer peripheral surface of the intermediate shaft part, a smooth curved surface in

more forward side than the apex on the rotation direction is formed toward the outer

peripheral surface of the intermediate shaft part. Therefore, when the lubricating oil is

stirred by the rotating shaft, the lubricating oil is from the eccentric-side curved surface

toward the apex-side curved surface by these surfaces and flows smoothly. Therefore,

even in the intermediate shaft part having the apex, the stirring loss of the lubricating oil

can be reduced.

[0017]

Additionally, in the rotating shaft of the rotary compressor, a pair of the apexes

may be provided at positions symmetrical to each other with respect to the axis.

[0018]

In this way, by providing the apexes at the symmetrical positions, the lubricating

oil can be smoothly guided while securing the strength of the intermediate shaft part, and

the stirring loss of the lubricating oil during the rotation of the rotating shaft can be further reduced. Moreover, during rotation, centrifugal forces acting on the positions of the apexes of the intermediate shaft part can be canceled between the apexes, and the stability during the rotation of the rotating shaft can be improved.

[0019]

Additionally, in the rotating shaft of the rotary compressor, the pair of apexes

may be different from each other in shift amount of an angle toward the backward side in

the rotational direction with respect to a direction orthogonal to the eccentric direction.

[0020]

Even in such a case, the lubricating oil can be smoothly guided while securing

the strength of the intermediate shaft part, and the stirring loss of the lubricating oil

during the rotation of the rotating shaft can be reduced.

[0021]

Additionally, a rotary compressor according to one aspect of the invention

includes the rotating shaft, a drive unit that is configured to rotationally drive the rotating

shaft, and a casing that accommodates the rotating shaft and the drive unit and has a first

compression chamber and a second compression chamber therein.

[0022]

According to such a rotary compressor, by including the above rotating shaft,

when the rotating shaft rotates, the lubricating oil around the intermediate shaft part can

be smoothly guided toward the apex of the intermediate shaft part, can smoothly flow

along the outer peripheral surface of the intermediate shaft part toward the backward side

in the rotational direction, and the stirring loss of the lubricating oil can be reduced. It

is possible to increase the second moment of area of the intermediate shaft part compared

to a case where the apex is not provided, and it is possible to suppress the deflection

deformation of the rotating shaft.

[0023]

According to another form of the invention there is provided a rotating shaft of a

rotary compressor that is rotatably supported with respect to a casing having a

an apex where a distance between the outer peripheral surface and the axis is maximized

on an outer peripheral surface of the intermediate shaft part, wherein the outer peripheral

surface of the intermediate shaft part is disposed within one region where an outer

shaft piston rotor overlap each other as viewed in the cross section orthogonal to the axis,

and wherein the intermediate shaft part has a shape in which only a portion of each apex

on a forward side of the rotational direction is partially cut off radially inward from said

one region when the intermediate shaft part is viewed in a cross section orthogonal to the

axis such that the apex is disposed at a position shifted at an angle larger than 0 degrees and smaller than 5 degrees toward the backward side in the rotational direction with respect to an imaginary line passing through the axis orthogonally to the eccentric direction.

[0024]

rotary compressor that is rotatably supported with respect to a casing having a

maximized on an outer peripheral surface of the intermediate shaft part, wherein the

intermediate shaft part has a shape in which only a portion of the apex on a forward side

of the rotational direction is partially cut off radially inward from one region where an

outer peripheral edge of the main shaft piston rotor and an outer peripheral edge of the

sub-shaft piston rotor overlap each other, when the intermediate shaft part is viewed in a cross section orthogonal to the axis such that the apex is disposed at a position shifted at an angle larger than 0 degrees and smaller than 45 degrees toward a backward side in a rotational direction with respect to an imaginary line passing through the axis orthogonally to the eccentric direction, wherein a pair of the apexes is provided at positions symmetrical to each other with respect to the axis, and wherein the pair of apexes is different from each other in shift amount of an angle toward the backward side in the rotational direction with respect to a direction orthogonal to the eccentric direction.

Advantageous Effects of Invention

[0025]

According to the rotating shaft of the rotary compressor, and the rotary

compressor, by virtue of the above configuration, it is possible to suppress the deflection

of the rotating shaft to increase efficiency.

[0026]

Where any or all of the terms "comprise", "comprises", "comprised" or

"comprising" are used in this specification (including the claims) they are to be interpreted

as specifying the presence of the stated features, integers, steps or components, but not

precluding the presence of one or more other features, integers, steps or components.

BRIEF DESCRIPTION OF DRAWINGS

[0027]

FIG. 1 is a longitudinal sectional view of a rotary compressor according to an

embodiment of the invention.

FIG. 2 is a view showing a rotating shaft of the rotary compressor according to

the embodiment of the invention.

FIG. 3 is a sectional view showing an intermediate shaft part in the rotating shaft

10a

of the rotary compressor according to the embodiment of the invention and is a view

showing cross section A-A of FIG. 2.

FIG. 4A is a graph of experimental results showing a relationship between a load

direction (maximum gas load direction) of a refrigerant gas and a load (maximum gas

load) caused by the refrigerant gas during the compression of acting on the rotating shaft

of the rotary compressor according to the embodiment of the invention.

FIG. 4B is a graph of experimental results showing a relationship between an angle c formed with an imaginary line Y at the apex and a pressure ratio HP/LP according to the embodiment of the invention.

FIG. 5 is a sectional view showing an intermediate shaft part in the rotating shaft

of a rotary compressor according to the first modification example of the embodiment of

the invention.

FIG. 6 is a sectional view showing an intermediate shaft part in a rotating shaft

of a rotary compressor according to the second modification example of the embodiment

of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0028]

Hereinafter, a rotary compressor 1 according to an embodiment of the invention

will be described.

As shown in FIG. 1, the rotary compressor 1 includes a drive unit 18, a rotating

shaft 15 rotationally driven by the drive unit 18, and a casing 11 that accommodates the

drive unit 18 and the rotating shaft 15. The rotary compressor 1 is a so-called two

cylinder type rotary compressor 1 in which compression chambers S are provided in two

upper and lower stages at an inner lower part of the casing 11.

[0029]

The casing 11 has a cylindrical shape centered on an axis 0, and two disk

shaped cylinders 12A and 12B are provided at a distance in an upward-and-downward

direction at an inner lower part of the casing 11. An upper cylinder is referred to a

main-shaft-side cylinder 12A, and a lower cylinder is referred to as a sub-shaft-side

cylinder 12B.

Cylindrical cylinder inner wall surfaces 12S1 and 12S2 are formed inside the cylinders 12A and 12B, respectively. The first compression chamber Si is defined by the cylinder inner wall surface 12S1 of the main-shaft-side cylinder 12A, and the second compression chamber S2 is defined by the cylinder inner wall surface 12S2 of the sub shaft-side cylinder 12B. Adisk-shaped partition plate 10 is provided between the upper and lower cylinders 12A and 12B. The first compression chamber S Iand the second compression chamber S2 are partitioned by the partition plate 10.

[0030]

Openings 22A and 22B are formed at the positions of a side surface, i.e., an

outer peripheral surface of the casing 11, which face outer peripheral surfaces of the

main-shaft-side cylinder 12A and the sub-shaft-side cylinder 12B. Suction ports 23A

and 23B communicating with the first compression chamber S and the second

compression chamber S2 are respectively formed at the positions of the cylinders 12A

and 12B facing the openings 22A and 22B.

[0031]

An accumulator 24, which performs gas-liquid separation of the refrigerant

taken in from the upper suction inlet 24a before the refrigerant (fluid) is introduced into

the casing 11, is fixed to the casing 11 via a stay 25. The accumulator 24 is provided

with suction pipes 26A and 26B for introducing a gaseous phase of the refrigerant

separated into gas and liquid in the accumulator 24 into thefirst compression chamber S1

and the second compression chamber S2 in the casing 11. Distal end parts of the

suction pipes 26A and 26B are connected to the suction ports 23A and 23B through the

openings 22A and 22B.

[0032]

Additionally, an upper part of the casing 11 is provided with discharge port 27

through which the refrigerant compressed in the first compression chamber S and the second compression chamber S2 is discharged.

[0033]

The drive unit 18 is an electric motor and has a stator 20 fixed to an inner

surface of the casing 11 above the main-shaft-side cylinder 12A, and a rotor 19 disposed

so as to face the stator 20 inside the stator 20.

[0034]

As shown in FIG. 2, the rotating shaft 15 includes a shaft main body 16 having a

rod shape that extends in the direction of the axis 0 around the axis 0, a main shaft

piston rotor 14A and a sub-shaft piston rotor 14B that are provided in the shaft main body

16, and an intermediate shaft part 17 that is disposed at the position sandwiched between

the main shaft piston rotor 14A and the sub-shaft piston rotor 14B in the direction of the

axis 0.

[0035]

The shaft main body 16 is provided so as to be fitted into the rotor 19 of the

drive unit 18 and is rotated around the axis 0 together with the rotor 19 by supplying

electric power to the drive unit 18. The shaft main body 16 is rotatably supported on

the casing 11 by an upper bearing 17A provided at an upper part of the main-shaft-side

cylinder 12A, and a lower bearing 17B provided at a lower part of the sub-shaft-side

cylinder 12B.

[0036]

The main shaft piston rotor 14A is provided in the shaft main body 16, is

accommodated in the first compression chamber S, and is rotated around the axis 0

together with the shaft main body 16. The main shaft piston rotor 14A is formed

integrally with the shaft main body 16, is externally fitted to a main-shaft-side shaft part

13A having a columnar shape centered on an eccentric axis 01 parallel to the axis 0, and has an annular shape. Accordingly, the main shaft piston rotor 14A rotates eccentrically with respect to the shaft main body 16 if the shaft main body 16 rotates.

[0037]

The sub-shaft piston rotor 14B is provided in the shaft main body 16, is

accommodated in the second compression chamber S2, and is rotated around the axis 0

together with the shaft main body 16. The sub-shaft piston rotor 14B is formed

integrally with the shaft main body 16, is externally fitted to a sub-shaft-side eccentric

shaft part 13B having a columnar shape centered on an eccentric axis 02 parallel to the

axis 0 and the eccentric axis 01, and has an annular shape. The eccentric axis 02 is

disposed at a position symmetrical to the eccentric axis 01 with respect to the axis 0.

That is, the main shaft piston rotor 14A and the sub-shaft piston rotor 14B are

rotated in a state where 180 degrees phases are eccentric in different directions with

respect to the shaft main body 16.

[0038]

Here, the rotating shaft 15 may be formed such that a main shaft portion

provided with the main shaft piston rotor 14A and a sub-shaft portion provided with the

sub-shaft piston rotor 14B are separately manufactured and these portions are joined

together, or may be integrally formed. The main shaft portion and the sub-shaft portion

may have mutually different external diameters.

[0039]

Next, the intermediate shaft part 17 will be described.

As shown in FIG. 2, the intermediate shaft part 17 is provided at the position

sandwiched between the main shaft piston rotor 14A and the sub-shaft piston rotor 14B

in the direction of the axis 0. That is, the intermediate shaft part 17 is disposed between

the main-shaft-side cylinder 12A and the sub-shaft-side cylinder 12B within the casing

11.

[0040]

As shown in FIG. 3, when the intermediate shaft part 17 is viewed in a cross

section orthogonal to the axis 0, an outer peripheral surface of the intermediate shaft part

17 is disposed within one region AR where an outer peripheral edge 14Aa of the main

shaft piston rotor 14A and an outer peripheral edge 14Ba of the sub-shaft piston rotor

14B overlap each other. More specifically, in the present embodiment, the outer

peripheral surface of the intermediate shaft part 17 is disposed within a region where an

outer peripheral edge 13Aa of the main-shaft-side shaft part 13A and an outer peripheral

edge 13Ba of the sub-shaft-side eccentric shaft part 13B overlap each other.

[0041]

That is, the sectional shape of the intermediate shaft part 17 is a substantially

elliptical shape, rugby ball shape, or almond shape. Accordingly, the intermediate shaft

part 17 has a pair of apexes 17a that protrudes toward both sides in a direction

intersecting an eccentric direction that is a direction in which an imaginary line X

connecting the eccentric axes 01 and 02 and the axis 0 over the entire area in the

direction of the axis 0 extend.

[0042]

The pair of apexes 17a is provided at positions symmetrical to each other with

respect to the axis 0. Each apex 17a is disposed at a position by an angle a toward a

backward side in a rotational direction R of the rotating shaft 15 with respect to an

imaginary line Y that extends in the direction orthogonal to the eccentric direction, and

thereby, the external diameter dimension of the intermediate shaft part 17 is the largest at

the position of the angle u. Additionally, the external diameter dimension of the

intermediate shaft part 17 is the smallest in the eccentric direction.

[0043]

An outer peripheral surface of the apex 17a has an arcuate apex-side curved

surface 17b that is disposed at a position apart from the outer peripheral edge 13Aa or

13Ba that is an outer edge of the one region AR, that is, radially inward of the outer edge

and is curved in a convex shape from the apex 17a in a direction away from the axis 0

toward a forward side in the rotational direction R, and the arcuate eccentric-side curved

surface 17c continuous with the apex 17a.

[0044]

Since the pair of apexes 17a is provided in the present embodiment, a pair of

apex-side curved surfaces 17b is provided at positions symmetrical to each other with

respect to the axis 0.

Here, the curvature radius of the apex-side curved surface 17b is preferably as

large as possible in order to keep the second moment of area of the intermediate shaft

part 17.

[0045]

The eccentric-side curved surface 17c is smoothly continuous with the apex-side

curved surface 17b in a state where there is no angle on the forward side in the rotational

direction of the apex 17a. Also, the eccentric-side curved surface 17c is provided at a

position including an intersection point P between the imaginary line X extending in the

above eccentric direction, and an outer edge of the one region AR, and extends on the

outer edge along the outer edge.

[0046]

Since the pair of apexes 17a is provided in the present embodiment, a pair of the

eccentric-side curved surfaces 17c of the positions symmetrical to each other with respect

to the axis 0 is provided. Accordingly, one eccentric-side curved surface 17c extends along the outer edges of one region AR continuously on the forward side in the rotational direction R with one apex-side curved surface 17b extending toward the forward side in the rotational direction from one apex 17a, and is connected to the other apex 17a.

Additionally, the other eccentric-side curved surface 17c is continuous on the forward

side in the rotational direction R with the other apex-side curved surface 17b extending

toward the forward side in the rotational direction R from the other apex 17a, extends

along the outer edge of the one region AR, and is connected to the one apex 17a.

In other words, the intermediate shaft part 17 has a shape in which a portion of a

forward portion in the rotational direction of the apex 17a is cut off radially inward from

the substantially elliptical shape, rugby ball shape, or almond shape by the apex-side

curved surface 17b.

Here, when the apex-side curved surface 17b is machined, in order to machine

the apex-side curved surface while suppressing the amount of cutting, for example, it is

possible to dispose the center of a machining circle on the backward side in the rotational

direction R of the rotating shaft 15 with respect to the imaginary line Y to shave the

intermediate shaft part 17 in an arcuate shape. Moreover, although an angle 6 from the

imaginary line Y to a connection point between the apex-side curved surface 17b and the

eccentric-side curved surface 17c continuous toward the forward side in the rotational

direction with the apex-side curved surface 17b is a value larger than the angle ( < 6),

6 may be a value that is as close to as possible.

[0047]

Here, the value of the above angle c is, for example, a value larger than 0

degrees and smaller than 5 degrees in the present embodiment.

As shown in FIG. 4A, FIG. 4B, and Table 1, under any condition (HP

(discharge-side pressure)/LP (suction-side pressure)), it could be confirmed from

experimental results that the maximum gas load acts in a range larger than 5 degrees and

smaller than 41 degrees toward the backward side in the rotational direction R with

reference to the imaginary line Y that extends in the direction orthogonal to the eccentric

direction in the intermediate shaft part 17. That is, the range where the maximum gas

load acts is a range ofc= 5 degrees to 41 degrees.

[0048]

[Table 1]

Gasmu [N] X 1.18X 1.25X 1.16X Maximum GasLoad [deg] 96 110 128 142 Direction Angle Formed With [deg] 5 14 29 41 Imaginary Line: a Pressure Ratio: [-] 2.8 4.1 8.6 21.5 HP/LP Additionally, the value of HP/LP in Table 1 was set assuming HP/LP in general

air conditioners.

[0049]

According to the rotary compressor 1 of the present embodiment described

above, the apex 17a of the intermediate shaft part 17 is disposed at a position shifted at

an angle larger than 0 degrees and smaller than 5 degrees toward the backward side in the

rotational direction R with respect to the direction orthogonal to the eccentric direction.

That is, the apex 17a is not disposed on the imaginary line Y that extends in the direction

orthogonal to the eccentric direction.

[0050]

Therefore, since the diameter of the intermediate shaft part 17 is maximized at a

position where the apex 17a is provided, the second moment of area of the intermediate

shaft part 17 can be increased at this position, and the rigidity of the intermediate shaft

part 17 can be improved. Therefore, even when the load during compression acts on

each of the piston rotors 14A and 14B, it is possible to suppress deflection deformation of

the rotating shaft 15.

[0051]

Particularly, as shown in the above FIG. 4A, FIG. 4B, and Table 1, the knowledge that the maximum load during compression acts in a range of 5 degrees or more and 41 degrees or less toward the backward side in the rotational direction R with respect to the intermediate shaft part 17 was obtained. Therefore, the maximum load during compression does not act on the forward side in the rotational direction R from the apex 17a.

[0052]

In this regard, in the present embodiment, the apex 17a is disposed at the

position shifted by the angle a larger than 0 degrees and smaller than 5 times toward the

backward side in the rotational direction R with respect to the direction orthogonal to the

eccentric direction. Thus, the thickness of the intermediate shaft part 17 on the forward

side in the rotational direction R from the apex 17a is smaller than that of a columnar

shape.

However, in the portion in which the thickness of this intermediate shaft part 17

is smaller, as described above, the load acting during compression is smaller than the

maximum load. Therefore, even if the apex 17a is provided at the above position, the

strength of the intermediate shaft part 17 can be sufficiently secured. Also, the weight

of the intermediate shaft part 17 can also be reduced.

[0053]

Additionally, in the present embodiment, the outer peripheral surface of the

intermediate shaft part 17 is disposed within the one region AR where the outer

peripheral edge of the main shaft piston rotor 14A and the outer peripheral edge of the

sub-shaft piston rotor 14B overlap each other, and the apex 17a is formed such that the

outer peripheral surface of the intermediate shaft part 17 is cut off on the forward side in

the rotational direction R of the apex 17a. For this reason, when the rotating shaft 15

rotates, the lubricating oil present around the intermediate shaft part 17 is smoothly guided toward the apex 17a of the intermediate shaft part 17, and smoothly flows along the outer peripheral surface of the intermediate shaft part 17 toward the backward side in the rotational direction R. Therefore, the stirring loss when the lubricating oil is stirred by the intermediate shaft part 17 during rotation can be reduced.

[0054]

Particularly, in the present embodiment, by providing the apex-side curved

surface 17b and the eccentric-side curved surface 17c as the outer peripheral surfaces of

the intermediate shaft part 17, a smooth curved surface having no angle from the above

intersection point P toward the apex 17a is formed on the outer peripheral surface of the

intermediate shaft part 17 on the forward side in the rotational direction R from the apex

17a. Hence, when the lubricating oil is stirred by the rotating shaft 15, the lubricating

oil is guided from the eccentric-side curved surface 17c toward the apex-side curved

surface 17b by these surfaces and flows smoothly. Therefore, even in the intermediate

shaft part 17 having the apex 17a, the stirring loss of the lubricating oil can be reduced.

[0055]

Moreover, by providing a pair of apexes 17a at the positions symmetrical to each

other with respect to the axis 0, the lubricating oil can be smoothly guided on the outer

peripheral surface of the intermediate shaft part 17 while securing the strength of the

intermediate shaft part 17, and the stirring loss of the lubricating oil can be further

reduced. Moreover, during rotation, centrifugal forces acting on the positions of the

apexes 17a of the intermediate shaft part 17 can be canceled between the apexes 17a, and

the stability during the rotation of the rotating shaft 15 can be improved.

[0056]

Although the embodiments of the invention have been described in detail with

reference to the drawings, the respective configurations and combinations thereof in the respective embodiments are examples, additions, omissions, substitutions, and other modifications of components can be made without departing from the concept of the invention. Additionally, the invention is not limited by the embodiment, and is limited only by the claims.

For example, as shown in FIG. 5, the apex 17a may be provided only at one

point. The apex 17a is disposed at a position shifted by an angle P larger than 0 degrees

and smaller than 5 degrees toward the backward side in the rotational direction R with

respect to the imaginary line Y orthogonal to the eccentric direction.

[0057]

Moreover, as shown in FIG. 6, the pair of apexes 17a is provided, and the

positions at which the respective apexes 17a are disposed are disposed at positions

shifted by 01 and 02 toward the backward side in the rotational direction R with respect

to the imaginary line Y orthogonal to the eccentric direction. 01 and 02 are mutually

different angles, and both are angles larger than 0 degrees and smaller than 5 toward the

backward side in the rotational direction R with respect to the imaginary line Y

orthogonal to the eccentric direction.

[0058]

Additionally, the apex-side curved surface 17b of the intermediate shaft part 17

may be formed, for example, in a planar shape without being limited to the arcuate

curved surface.

[0059]

Additionally, the apex 17a may be disposed outside the one region AR.

[0060]

Additionally, although the above angles u, P, 01, and 02 are, for example, values larger than 0 degrees and smaller than 5 degrees, the angles are not limited to this. That is, since the apex 17a to where the distance from the axis 0 is maximized may be located at the position where the maximum load acts on the intermediate shaft part 17, the values of u, P, 01, and 02 may be larger than 0 degrees and smaller than 45 degrees.

Particularly, in a case where the apex 17a is disposed outside the one region AR, the

diameter of the intermediate shaft part 17 does not extremely decreases on the backward

side in the rotational direction R of the apex 17a. Thus, in consideration of this point,

c, P, 01, and 02 may not be limited to the value larger than 0 degrees and smaller than 5

degrees as described above.

Industrial Applicability

[0061]

According to the rotating shaft of the rotary compressor, and the rotary

of the rotating shaft to increase efficiency.

Reference Signs List

[0062]

1: rotary compressor

10: partition plate

11: casing

12A: main-shaft-side cylinder

12B: sub-shaft-side cylinder

12S1, 12S2: cylinder inner wall surface

13A: main-shaft-side shaft part

13B: sub-shaft-side eccentric shaft part

13Aa, 13Ba: outer peripheral edge

14A: main shaft piston rotor

14B: sub-shaft piston rotor

14Aa, 14Ba: outer peripheral edge

15: rotating shaft

16: shaft main body

18: drive unit

17: intermediate shaft part

17a: apex

17b: apex-side curved surface

17c: eccentric-side curved surface

19: rotor

20: stator

22A: opening

22B: opening

23A: suction port

23B: suction port

24: accumulator

24a: suction inlet

25: stay

26A: suction pipe

26B: suction pipe

27: discharge port

S: compression chamber

Si: first compression chamber

S2: second compression chamber

R: rotational direction

0: axis

01: eccentric axis

02: eccentric axis

AR: one region

X: imaginary line

P: intersection point

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A rotating shaft of a rotary compressor that is rotatably supported with

respect to a casing having a compression chamber therein and is rotationally driven

around an axis to allow a fluid to be compressed with lubricating oil, the rotating shaft

comprising:

a shaft main body that extends in a rod shape around the axis;

a main shaft piston rotor that is eccentrically provided at the shaft main body

and is accommodated in a first compression chamber in the compression chamber;

a sub-shaft piston rotor that is disposed apart in a direction of the axis from the

main shaft piston rotor, is provided eccentrically with respect to the shaft main body in a

direction different in phase by 180 degrees from the main shaft piston rotor, and is

accommodated in a second compression chamber in the compression chamber; and

an intermediate shaft part around which the lubricating oil is present and which

is provided at a position sandwiched between the main shaft piston rotor and the sub

shaft piston rotor in the shaft main body,

wherein the intermediate shaft part protrudes in a direction intersecting an

eccentric direction of the main shaft piston rotor and the sub-shaft piston rotor as viewed

in a cross section orthogonal to the axis, and has at least one apex where a distance

between the outer peripheral surface and the axis is maximized on an outer peripheral

surface of the intermediate shaft part,

wherein a pair of the apexes is provided at positions symmetrical to each other

with respect to the axis, and

wherein the intermediate shaft part has a shape in which only a portion of the

apex on a forward side of the rotational direction is partially cut off radially inward from one region where an outer peripheral edge of the main shaft piston rotor and an outer peripheral edge of the sub-shaft piston rotor overlap each other, when the intermediate shaft part is viewed in a cross section orthogonal to the axis such that the apex is disposed at a position shifted at an angle larger than 0 degrees and smaller than 45 degrees toward a backward side in a rotational direction with respect to an imaginary line passing through the axis orthogonally to the eccentric direction.

2. The rotating shaft of a rotary compressor according to claim 1,

wherein the outer peripheral surface of the intermediate shaft part is disposed

within one region where an outer peripheral edge of the main shaft piston rotor and an

outer peripheral edge of the sub-shaft piston rotor overlap each other as viewed in the

cross section orthogonal to the axis.

3. A rotating shaft of a rotary compressor that is rotatably supported with

comprising:

a shaft main body that extends in a rod shape around the axis;

a main shaft piston rotor that is eccentrically provided at the shaft main body

and is accommodated in a first compression chamber in the compression chamber;

accommodated in a second compression chamber in the compression chamber; and

an intermediate shaft part around which the lubricating oil is present and which is provided at a position sandwiched between the main shaft piston rotor and the sub shaft piston rotor in the shaft main body, wherein the intermediate shaft part protrudes in a direction intersecting an eccentric direction of the main shaft piston rotor and the sub-shaft piston rotor as viewed in a cross section orthogonal to the axis, and has an apex where a distance between the outer peripheral surface and the axis is maximized on an outer peripheral surface of the intermediate shaft part, wherein the outer peripheral surface of the intermediate shaft part is disposed within one region where an outer peripheral edge of the main shaft piston rotor and an outer peripheral edge of the sub-shaft piston rotor overlap each other as viewed in the cross section orthogonal to the axis, and wherein the intermediate shaft part has a shape in which only a portion of each apex on a forward side of the rotational direction is partially cut off radially inward from said one region when the intermediate shaft part is viewed in a cross section orthogonal to the axis such that the apex is disposed at a position shifted at an angle larger than 0 degrees and smaller than 5 degrees toward the backward side in the rotational direction with respect to an imaginary line passing through the axis orthogonally to the eccentric direction.

4. The rotating shaft of a rotary compressor according to claim 2 or 3,

wherein the outer peripheral surface of the intermediate shaft part includes an

apex-side curved surface that is disposed inside an outer edge of the one region and

extends to be curved in a convex shape in a direction away from the axis toward a

forward side in the rotational direction from the apex, and

an eccentric-side curved surface that is continuous with the apex-side curved surface with a smooth connection therebetween and is provided at a position including an intersection point between the imaginary line extending in the eccentric direction and the outer edge of the one region to extend along the outer edge of the one region.

5. A rotating shaft of a rotary compressor that is rotatably supported with

comprising:

a shaft main body that extends in a rod shape around the axis;

a main shaft piston rotor that is eccentrically provided at the shaft main body

and is accommodated in a first compression chamber in the compression chamber;

accommodated in a second compression chamber in the compression chamber; and

shaft piston rotor in the shaft main body,

wherein the intermediate shaft part protrudes in a direction intersecting an

surface of the intermediate shaft part,

wherein the intermediate shaft part has a shape in which only a portion of the

apex on a forward side of the rotational direction is partially cut off radially inward from one region where an outer peripheral edge of the main shaft piston rotor and an outer peripheral edge of the sub-shaft piston rotor overlap each other, when the intermediate shaft part is viewed in a cross section orthogonal to the axis such that the apex is disposed at a position shifted at an angle larger than 0 degrees and smaller than 45 degrees toward a backward side in a rotational direction with respect to an imaginary line passing through the axis orthogonally to the eccentric direction, wherein a pair of the apexes is provided at positions symmetrical to each other with respect to the axis, and wherein the pair of apexes is different from each other in shift amount of an angle toward the backward side in the rotational direction with respect to a direction orthogonal to the eccentric direction.

6. A rotary compressor comprising:

the rotating shaft according to any one of claims I to 5;

a drive unit that is configured to rotationally drive the rotating shaft; and

a casing that accommodates the rotating shaft and the drive unit and has a first

compression chamber and a second compression chamber therein.